The present invention relates to a scanning type tunnel microscope for measuring a tunnel current flowing between a scanning probe and an observation surface of a sample while they are kept at a minimum distance, e.g., 50.ANG. or less, and moving the scanning probe in the axial direction to always obtain a constant tunnel current, thereby obtaining an image of the observation surface.
A microscope of this type allows observation of the surface structure of a sample with high resolution on the order of several angstroms or less, and will not damage the observation surface of the sample at all. In this manner, the microscope has superior characteristics to those of microscopes of other types.
However, conventionally, in order to obtain such a high resolution, a known scanning type tunnel microscope described in U.S. Pat. No. 4,343,993 must have a structure for preventing the influence of external vibration as much as possible, and its main part must be housed in a vacuum chamber to be driven in high vacuum. For this reason, the entire apparatus becomes bulky, and an operation is cumbersome.